The present invention relates to a tissue marking system. More particularly, the present invention relates to a tissue marking system that includes ink.
Successful breast cancer conservation surgery requires complete removal of the cancerous tumor while preserving sufficient surrounding healthy breast tissue. The most important predictor of local cancer recurrence is the status of the margins, the distance between the tumor and the tissue edge. Close or transected margins generally require an additional surgical procedure to re-excise the close or transected margin. Therefore, knowing the exact position of the close or transected margin that requires further excision is critical, because it provides direction from the pathology analysis to the surgeon on where cancerous cells may remain in the patient's body. In breast cancer surgery, re-excision rates run as high as 30-40%.
Currently, among many surgeons the most common method of identifying the tissue margins for pathology analysis is with sutures. However, there are significant risks associated with using suture to orient tissue. First, suture provides ambiguous and incomplete orientation information. In other words, the original position of the specimen in the patient's body is unclear to the pathologist who must decide whether the margins are sufficiently clear of cancer. In addition, the entire edge of each of the six tissue margins is undefined; therefore the pathologist does not know where one margin ends and the next margin begins. The Annals of Surgical Oncology reported a 31% error rate when sutures were used to orient excised tissue. A suture cannot represent the entire margin plane and requires the pathologist to estimate the margin boundaries. The ambiguity and incompleteness of the suture method creates the potential for: 1) unnecessary re-excision, or additional surgery for the patient. This brings the additional risks of a second surgery; 2) an unnecessarily large amount of tissue removed during re-excision; and 3) inaccurate re-excision which may result in cancer recurrence.
Another problem associated with using sutures is that it exposes surgeons and nurses to the risk of puncture wounds. This is a significant problem for healthcare workers: the World Health Organization estimates that 9% of health care professionals will experience percutaneous exposure to bloodborne pathogens each year; such incidents carry the risk of contagious diseases such as Hepatitis C and HIV. Each needle injury costs the hospital approximately $3,000 in testing and treatments. The invention claimed by '249 patent increases safety in the operating room by eliminating the risk of using suture as it applies to orienting excised tissue.
A less common alternative to using suture to orient specimens is to use ink applied in the operating room by the surgeon. Use of commercially available ink to identify tissue margins can reduce re-excisions by 50% and reduce the volume of tissue removed by 73%. However, margin definition may still be a problem because the majority of inks available on the market today run when applied to tissue, distorting the margin definition. This is a greater problem in areas of the specimen which are irregular (not smooth). If the ink runs into crevasses or under flaps of tissue, it may cause an unacceptable increase in false positive margins in the pathology analysis. False positive margins can result in the patient undergoing unnecessary surgery to re-excise tissue or mastectomy. Commercially available non-sterile inks require that the surgeon leave the sterile field during the operation to apply ink to the specimen. This involves an extra change of gown and gloves, which is inefficient. It also introduces an additional opportunity for error in marking the specimen margins because the specimen is transported away from the patient to another area of the operating room.
During surgery, it is often necessary to remove a sample of tissue and closely examine that tissue sample while knowing its original orientation within the patient. For example, cancerous tumors are often removed from the patient and then examined to verify that a sufficient margin of tissue surrounding the tumor has been removed. To determine this, the tissue sample is examined and the margins on each surface are identified. Should a margin be insufficient, it is important for the surgeon to know the orientation of the sample to allow for the removal of additional tissue in the proper area.
Presently, different color sutures, different length sutures, or different quantities of sutures are inserted into the tissue sample to identify the orientation of the tissue. However, this is time consuming and the sutures can be accidentally removed making identification of the tissue orientation difficult.
What is needed is a tissue marking system that overcomes the deficiencies of conventional marking systems.